Add an os.get_exec_path() function to return the list of directories
that launching a subprocess will search for the executable.
Refactors some code in os._execvpe().
diff --git a/Doc/library/os.rst b/Doc/library/os.rst
index d01c8da..0547154 100644
--- a/Doc/library/os.rst
+++ b/Doc/library/os.rst
@@ -136,6 +136,17 @@
These functions are described in :ref:`os-file-dir`.
+.. function:: get_exec_path(env=None)
+
+ Returns the list of directories that will be searched for a named
+ executable, similar to a shell, when launching a process.
+ *env*, when specified, should be an environment variable dictionary
+ to lookup the PATH in.
+ By default, when *env* is None, :data:`environ` is used.
+
+ .. versionadded:: 3.2
+
+
.. function:: ctermid()
Return the filename corresponding to the controlling terminal of the process.
diff --git a/Lib/os.py b/Lib/os.py
index 1c5b5ce..580b983 100644
--- a/Lib/os.py
+++ b/Lib/os.py
@@ -342,28 +342,23 @@
def _execvpe(file, args, env=None):
if env is not None:
- func = execve
+ exec_func = execve
argrest = (args, env)
else:
- func = execv
+ exec_func = execv
argrest = (args,)
env = environ
head, tail = path.split(file)
if head:
- func(file, *argrest)
+ exec_func(file, *argrest)
return
- if 'PATH' in env:
- envpath = env['PATH']
- else:
- envpath = defpath
- PATH = envpath.split(pathsep)
last_exc = saved_exc = None
saved_tb = None
- for dir in PATH:
+ for dir in get_exec_path(env):
fullname = path.join(dir, file)
try:
- func(fullname, *argrest)
+ exec_func(fullname, *argrest)
except error as e:
last_exc = e
tb = sys.exc_info()[2]
@@ -376,6 +371,18 @@
raise last_exc.with_traceback(tb)
+def get_exec_path(env=None):
+ """Returns the sequence of directories that will be searched for the
+ named executable (similar to a shell) when launching a process.
+
+ *env* must be an environment variable dict or None. If *env* is None,
+ os.environ will be used.
+ """
+ if env is None:
+ env = environ
+ return env.get('PATH', defpath).split(pathsep)
+
+
# Change environ to automatically call putenv(), unsetenv if they exist.
from _abcoll import MutableMapping # Can't use collections (bootstrap)
diff --git a/Lib/test/test_os.py b/Lib/test/test_os.py
index 1ff356c..9846d92 100644
--- a/Lib/test/test_os.py
+++ b/Lib/test/test_os.py
@@ -407,6 +407,27 @@
self.assertTrue(isinstance(env.data, dict))
self.assertEqual(repr(env), 'environ({!r})'.format(env.data))
+ def test_get_exec_path(self):
+ defpath_list = os.defpath.split(os.pathsep)
+ test_path = ['/monty', '/python', '', '/flying/circus']
+ test_env = {'PATH': os.pathsep.join(test_path)}
+
+ saved_environ = os.environ
+ try:
+ os.environ = dict(test_env)
+ # Test that defaulting to os.environ works.
+ self.assertSequenceEqual(test_path, os.get_exec_path())
+ self.assertSequenceEqual(test_path, os.get_exec_path(env=None))
+ finally:
+ os.environ = saved_environ
+
+ # No PATH environment variable
+ self.assertSequenceEqual(defpath_list, os.get_exec_path({}))
+ # Empty PATH environment variable
+ self.assertSequenceEqual(('',), os.get_exec_path({'PATH':''}))
+ # Supplied PATH environment variable
+ self.assertSequenceEqual(test_path, os.get_exec_path(test_env))
+
class WalkTests(unittest.TestCase):
"""Tests for os.walk()."""
diff --git a/Misc/NEWS b/Misc/NEWS
index 81dfbc0..8ce22ad 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -701,6 +701,9 @@
- Issue #6218: io.StringIO and io.BytesIO instances are now picklable.
+- The os.get_exec_path() function to return the list of directories that will
+ be searched for an executable when launching a subprocess was added.
+
Extension Modules
-----------------